Two tier hi-speed wireless communication link

ABSTRACT

A method and apparatus for mobile two-tier wireless communication are provided. A wireless communication signal may be received at a mobile communication device from a cellular base station. Data may be recovered from the received wireless communication signal. The data may be transmitted to an IEEE 802.11 user device. A second wireless communication signal may be received from the IEEE 802.11 user device. Data may be recovered from the second wireless communication signal. The data may be transmitted to the cellular base station.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/032,246, filed Feb. 22, 2011, which is a continuation of U.S. patentapplication Ser. No. 11/028,796, filed Jan. 4, 2005, which issued asU.S. Pat. No. 7,894,475 on Feb. 22, 2011, which is a continuation ofU.S. patent application Ser. No. 09/384,072, filed Aug. 26, 1999, whichissued as U.S. Pat. No. 6,850,512 on Feb. 1, 2005, the contents of whichare hereby incorporated by reference herein.

BACKGROUND

The widespread availability of low-cost personal computers has enhancedthe desire to relay tremendous volumes of information between parties incommunication over networks such as the Internet. A similar demandexists for wireless communication technology such as voice-basedcellular telephones due to the convenience afforded by mobileflexibility. It is not surprising, therefore, that there existsincreasing demand for combined technology supporting high speed datatransfers between interconnected computers over wireless communicationlinks.

One fairly low-cost solution supporting wireless communication is toconnect a computer to a modem and cellular phone to create a connectionwith an Internet service provider, thus, forming a wireless link betweena client computer and a network such as the Internet. Unfortunately,this type of link has several drawbacks. In particular, such a link isoften painstakingly slow due to the inefficiencies of combining the twotechnologies.

Part of the inefficiencies in mating wireless and network communicationsis due to their inherent architectures. For example, the protocols usedfor connecting computers over hardwired links do not easily lendthemselves to efficient transmission over standard wireless links, whichhave been designed for voice grade communications requiring continuousbut relatively slow data transfer rates.

Cellular networks were originally designed to provide voice gradecommunications, which typically require only a 3 Kilohertz bandwidth.Based on these techniques, the low frequency channels employed for voicecommunication are generally limited to a digital baud rate of 9.6kilobits per second (kbps), which is slow compared to transfer ratessuch as 56.6 kbps that are now commonly available in inexpensivewire-line modems. Notably, the reception of a sophisticated web page ata client computer based on wireless voice grade channels is slowcompared to the speed of a tethered modem connection to a hardwiredtelephone link. In short, it is similarly difficult to receive, ortransfer for that matter, any large files over standard voice basedtelephone systems.

Based on the increased desire to communicate with networks in thewireless sense, the Institute of Electrical and Electronics Engineers(IEEE) has developed a standard for Wireless Local Areas Networks(WLANS) known as 802.11. This standard focuses on resolvingcompatibility issues between manufacturers of WLAN equipment. In short,it supports a single hub topology that provides wireless links to aplurality of users, connecting each of them to a network link such as802.3 otherwise known as Ethernet. Based on this architecture, aplurality of computers are able to communicate with a network over awireless link eventually coupled to a hardwired link.

Unfortunately, the range of this wireless link with respect to thestationary hardwired link and hub is limited in range of up to 500meters. Moreover, the standard is further restrictive because hub istypically in communication with a network over a tethered Ethernet link.On a positive note, however, the standard provides high speed datatransfers over a plurality of short-range wireless communication links.

SUMMARY

The cost associated with wireless communication services can beprohibitive. For example, individual users typically sign up for afee-based wireless service entitling them to the use of a singlewireless link. This single subscription to a wireless link in additionto being slow is expensive when the total service cost for multipleusers is taken into consideration. The present invention focuses onsolving the problem by providing appropriate relief. In particular,sporadic and short term high throughput needs of individual end-usersare satisfied by the methods described herein at a total lower overallcommunication link cost.

One motivation of the present invention is to provide a method forsupporting increased mobility of remote terminals in communication witha network without unduly reducing data throughput on any of the links.When a group of users share a communication link for network access, itis recognized that typically only a sporadic high-speed throughputcapability is required by each user on a random basis. Hence, a singlehigh speed data throughput media can be shared by multiple users to gainaccess to remote networks. Accordingly, the principles of the presentinvention are advantageously deployed to satisfy the combinationaldesire for higher speed throughput and increased wireless mobileflexibility.

It is an advancement in the art to provide a method for communicatingbetween a plurality of remote terminals and a network, where the serialconnection of multiple types of communication media supports bothincreased user mobility and high speed access of information. Accordingto the principles of the present invention, a plurality of remotetransceivers communicate with a hub over a first type of wirelesscommunication link. The hub is coupled via a hardwired link to an accessunit, which further supports data transfers to a base station over asecond wireless communication link. This topology affords uniqueflexibility because it affords two-tiered mobility. Not only are theplurality of remote transceivers mobile with respect to the hub,likewise, the hub and access unit are potentially mobile or portablewith respect to the base station. Notably, the methods of the presentinvention assure that high speed data transfer rates are not sacrificedin lieu of increased mobility.

In a preferred embodiment of the present invention, the first wirelesslink supports private non-fee based, short-range data flows between theplurality of remote transceivers and the hub. The second wireless link,in communication with the hub via a hardwired link, supports longerrange communications such as data flows over a subscription-based link.Encryption techniques are optionally implemented on this link, and otherlinks in the system for that matter, for increased security ofcommunications.

Establishing the second wireless link includes making available aplurality of channels for use in data flows, where the channels utilizedto create data flows on an as-needed basis. Typically, a data rate onany given channel is unable to support an acceptable transfer rate.Therefore, multiple available channels are simultaneously utilized toprovide higher throughput data flows on the second wirelesscommunication link. In the preferred embodiment, these channels are ofthe CDMA-type as used in typical cellular telephone communication links.

In the preferred embodiment, a protocol is employed at the physicallayer level of the second wireless link to coordinate reformatting,partitioning, transmitting, receiving and reconstructing originalpackets, such as network messages. In short, the extra layer provides amethod of repackaging data for transmission over the second wirelesslink. This extra package layer is than stripped at a receiver end of thesecond wireless link, resulting in the originally formatted data, whichis further transmitted to a destination. Based on this technique, theplurality of remote transceivers and terminal equipment are seamlesslyconnected to a network at a remote location. Accordingly, remote usersare afforded potentially the same high-speed data transfer rates as ifthe remote terminal equipment and transceivers were connected to anetwork via a hard-wired link such as a standard voice-based telephoneline.

A WLAN, preferably a CSMA/CA or “listen-before-talk” scheme, is adoptedfor use on the first wireless communication link. This technique is usedin IEEE 802.11 standard, which is one viable method for supporting dataflows between the hub and plurality of transceivers. The use of anEthernet, IEEE 802.3 standard, is also the preferred type of hardwiredlink, however, other viable links include designs based on token ringimplementations or other star network topologies.

Data flows are preferably established based on a network messageprotocol such as TCP/IP. In this way, terminal equipment, such ascomputers or the like, running application network programs can easilyinterface to remote transceivers, which need only repackage data beforetransmission over the first communication link. On the receive end, theextra layer is stripped off, resulting in the originally formattedmessages. This format is preferred because a common end networktypically expects received data packets to be in the same format asoriginally transmitted over the network, i.e., data emanating fromremote terminal equipment is in a network message format preferablyunderstood by the destination node such as a server on the Internet.

Although one or many radio frequency channels are typically used tosupport communication on the first wireless communication link, it isoptionally based on infrared. However, spread spectrum such as DSSS orFHSS around 2.4 GHz are preferably used in this typically shorter rangewireless communication link. Other types of radio frequencyimplementations, such as those based on 1.9 GHz are also acceptable. Forexample, a protocol such as Blue Tooth™ or Home RF™ is optionallyemployed to support communication on the first link according to theprinciples of the present invention.

Also, it should be noted that communication between the plurality ofremote transceivers or terminal equipment and network is bidirectional.For example, the same principles as previously discussed about dataflows directed from the remote transceivers to the network applyequally, but in a reverse manner, to data flows directed from thenetwork to the remote transceivers.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 illustrates the inventive two-tiered wireless communicationsystem and related components.

FIG. 2 provides further detail of the inventive two-tiered wirelesscommunication system and related components.

FIG. 3 is a diagram depicting how network layer data frames are dividedamong multiple physical links or channels.

FIG. 4 is a more detailed diagram showing how network layer frames aredivided into subframes by a protocol converter located at a sendingunit.

FIG. 5 is a continuation of the diagram of FIG. 4.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a system for implementing high speed datacommunication over multiple media types according to the principles ofthe present invention. The system 190 includes a plurality of remotetransceivers 160 in eventual communication with network 140.

Remote transceivers 160 typically connect to terminal equipment (notshown) such as a portable or laptop computer, a desktop computer, aPersonal Digital Assistant (PDA), a ‘wearable’ computer or the like.Each remote transceiver 160 supports communication with hub 100 over afirst type of wireless communication link 150. For example, informationto be transferred from remote transceiver #1 160-1 is converted to aformat suitable for transmission such as in accordance with knowncommunication standards. In the preferred embodiment, terminal equipmentcoupled to each remote transceiver 160 transmits and receives data basedon a TCP/IP or other standard network protocol. In particular, networkmessages from remote transceiver #1 160-1 are transmitted over a firsttype of wireless communication link 150-1 from antenna 161-1 to create adata flow to hub 100 where the data is received on antenna 101.

It should be noted that data flows are also supported in the reversedirection in a similar manner such that data at the hub 100 istransferred over link 150-1 to the remote transceivers 161.

Communication link 110 coupling the hub 100 to access unit 120 providesfurther support of data flows. This link 110 is, for example, anEthernet type link based on IEEE 802.3 optionally comprising more thanone physical wire.

The system described thus far, including the remote transceiver 160 andhub 101, is optionally based on IEEE 802.11, which is a standard forWLANs. The 802.11 standard provides access to channels based on anaccess method known as Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA). In simple terms, this method is based on a “listenbefore talk” scheme. For example, a transceiver 160 must first monitortraffic on radio channel 150 to determine if another transceiver 160 istransmitting. If the radio channel 150 is clear, the transceiver 160 maytransmit information or frame over the radio channel 150. Based on thisCSMA/CA scheme, transmission of data from the same transmitter cannotoccur before a minimum time gap. After the minimum time gap has passed,the station selects a random “backoff interval” which is the wait timebefore the radio channel 150 is then monitored to determine whether itis clear to transmit. If the channel is still busy, a shorter backoffinterval is selected. This process is repeated until the transmitter isallowed to transmit data.

Network messages transmitted by remote transceivers typically include anextra protocol layer so that packets can be transmitted over the radiochannel 150 and, thereafter, be processed by hub 100 upon receipt. Oncereceived, the hub 100 strips off the extra layer to retrieve theoriginal network messages for routing to access unit over Ethernet link110. Likewise, network messages emanating from network 140 destined forone of the remote transceivers 160 are reformatted before transmissionover first wireless communication link 150. As in the former mentionedimplementation of data flows from a remote transceiver 160 to hub 100,an extra layer added by the hub 100 in the reverse direction is likewisestripped off by receiving remote transceiver 160. The original networkmessage(s) from hub 100 are then appropriately routed to coupledterminal equipment. In short, the extra layer is used to reformatnetwork messages, facilitating the transmission of such data overphysical link 30.

Further details of the aforementioned standard of transmitting databetween the plurality of remote transceivers 160 and hub 100 can befound in IEEE 802.11, which is available from IEEE located in Princeton,New Jersey. Likewise, the IEEE 802.3 standard related to Ethernetcommunication and link 110 is also available from the IEEE.

It should be noted that the use of IEEE 802.11 compliant equipment ismerely exemplary. Other wireless systems optionally support wirelesscommunication among a plurality of transceivers 160 and hub 100. Forexample, wireless link 150 is optionally infrared or some other type ofwireless communication link.

One desirable aspect of the first wireless link 150 is the ability tosupport higher speed data transfers. Based on the 802.11 standard asmentioned, DSSS for use with BPSK modulation provides a 1 Mega bit persecond (MBPS) data rate, or QPSK provides a 2 MBPS data rate. Likewise,the standard supports FHSS with GFSK modulation and two hopping patternsproviding data rates of 1 MBPS and 2 MPBS.

Another desirable aspect of the first wireless communication link 150 isits ability to support private non-fee based communications. Forexample, after an initial investment of hub 100 and remote transceiverequipment 160, no costs other than maintenance or upgrades arenecessarily incurred by users for mere use of this part of thecommunication system 190.

To some extent, communication on hub 100 already provides a level ofsecurity against intruders because frequency hopping techniques aregenerally used to transmit data. Additionally, the system is optionallydesigned to include encryption of data so that data flows over the firstcommunication link 150 are further protected from eavesdroppers tryingto gain access to, for example, vital corporate communications.

The long-range second wireless link 30 preferably operates on a publicfee-based service incorporating the use of cellular equipment such as aground or satellite base station. Although there is typically a costincurred for use of this link 30 in the system 190, such subscriptioncosts are minimized because multiple channels are utilizedsimultaneously to support data flows. Hence, a single subscriptionsupporting the use of many channels to provide high speed data flows issuperior to the higher cost associated with a group of individuals eachsigning up for many slower speed single subscription-based links. Thesecost savings are beneficially passed on to the operators of the system,rendering it possible to provide communications among a mass of users ata lower overall cost.

An alternative method of providing high speed data flows between remotetransceivers 160 and hub 100 is the Bluetooth™ baseband protocol, whichrelies on frequency hopping transceivers to combat interference andfading.

Based on the Bluetooth™ baseband protocol, a combination of circuit andpacket switching is deployed to support data transfer rates of up to 1MBPS. The normal link range is 10 cm to 10 meters, but transmit power isoptionally increased to provide links of up to 100 meters. Moreinformation regarding the Bluetooth™ baseband protocol and systemtopology can be found at web-site: http://www.bluetooth.net.

Another potential protocol for supporting communication on the firstwireless link is based on Home RF™. More information regarding thisprotocol is available at web-site: http://www.homerf.org

Regardless of the topology chosen for communication between hub 100 andremote transceivers 160, access unit 120 coupled to hub 100 via link 110provides further support of data flows to and from network 140.Specifically, a second wireless communication link 30 between the accessunit 120 and base station 130 affords high throughput of data trafficand mobility of the combined hub 100 and access unit 120. The allocationof multiple subchannels on the second wireless communication link 30between access unit antenna 121 and base station antenna 131 increasethroughput of the overall system many times over. Thus, throughput ofthe system does not suffer as a result of incorporating the secondwireless communication link 30 as multiple channels or CDMA forwardlinks simultaneously are utilized to create a high data throughput link.

The principles of the present invention, including the second wirelesscommunication link 30 are advantageous over existing techniques. Forexample, the techniques of providing a high speed communication linkbetween the access unit 120 and base station 130 in conjunction with thefirst wireless communication link 150 make it a unique two-tieredwireless system. Based on this topology, two-tier mobility is supportedbetween a plurality of transceivers 160 in communication with network140. A first tier allows remote transceiver 160 wireless mobileflexibility with respect to hub 100, while a second tier supportswireless mobile flexibility of combined hub 100 and access unit 120 withrespect to base station 130. It should be noted that further tier can beadded to support even further flexibility.

As mentioned, communication link 110 is preferably based on the IEEE802.3 (Ethernet) standard for contention networks. In particular, thestandard incorporates a bus or star topology and relies on Carrier SenseMultiple Access with Collision Detection capabilities (CSMA/CD) toregulate traffic on the link. Typically, this link is physically made oftwisted pair wire, a coaxial or fiber optic cable supporting data flowsof variable length data frames. Included with each frame or networkpacket are destination and control information for routing of packets tothe appropriate location. Based on this protocol, data flows aresupported between the hub 100 and access unit 120.

It should be noted that the use of an Ethernet link is merely exemplaryand that other types of links optionally provide the same functionality.Most importantly, communication link 110 preferably supports high speeddata flows from hub 100 to access unit 120. Additionally it is preferredthat an Ethernet type link 100 is used in conjunction with an 802.11 hub100 because the two are designed to be readily compatible for supportingnetwork data communications. However, any suitable network device isoptionally used such as other LAN devices. These include ring networks,other star networks, token bus networks, token pass networks, and tokenring networks.

Turning attention now to the details of the second wirelesscommunication link, FIG. 2 shows greater detail of access unit 120,second wireless communication link 30 and other blocks in FIG. 1.

Referring to FIG. 2, the subscriber or access unit 120 is incommunication with hub 100 via link 110. The hub 100 transmits data suchas network messages to a protocol converter 25, which in turn providesdata to a multichannel digital transceiver 26 and antenna 27.

Data flows on link 100 are preferably in a format suitable fortransmission such as in accordance with known communication standards.For example, hub 100 may convert data signals from the remotetransceivers 161 to a wireline physical layer protocol format such asspecified by the Integrated Services Digital Network (ISDN) standard atrates of 128 kbps, or the Kflex standard at rates of 56.6 kbps. At anetwork layer, the data provided by the hub 100 is preferably formattedin a manner consistent with suitable network communication protocolssuch as TCP/IP to permit the remote transceivers 161 and terminalequipment to connect to other computers over networks such as theInternet. This description of the hub 100 and preferred protocol isexemplary only and it should be understood that other protocols areoptionally used.

The protocol converter 25 implements an intermediate protocol layersuitable for converting the data provided by the hub 100 on link 110 toa format appropriate for the multichannel transceiver 26 according tothe invention, and as will be described in much greater detail below.

The multichannel digital transceiver 26 provides access to one or morephysical communication links such as the illustrated radio channels 30.The physical links are preferably known wireless communication airinterfaces using digital modulation techniques such as Code DivisionMultiple Access (CDMA) standard specified by IS-95. It should beunderstood that other wireless communication protocols and other typesof links 30 may also be used advantageously in the invention.

The channels 30 represent one or more relatively slower communicationchannels, such as those operating at a 9.6 kbps rate typical of voicegrade communication. These communications channels may be provided by asingle wide bandwidth CDMA carrier such as having a 1.25 MegaHertzbandwidth, and then providing the individual channels with uniqueorthogonal CDMA codes. Alternatively, the multiple channels 30 are basedon single channel communication media such as provided by other wirelesscommunication protocols. However, what is important is that the neteffect is that the channels 30 represent multiple communication channelsthat may be adversely effected by significant bit error rates that areunique to each link 30.

An “error” as described herein is a bit error perceived at the higherlayer such as the network layer. The invention only strives to improvethe system level bit error rate, and does not attempt to guaranteeabsolute data integrity.

At the local level, the service provider equipment 40 may for example beimplemented at a wireless Internet Service Provider (ISP) 40-1. In thiscase, the equipment includes an antenna 42-1, a multichannel transceiver44-1, a protocol converter 46-1, and other equipment 48-1 such asmodems, interfaces, routers, and the like which are needed for the ISPto provide connections to the Internet 49-1.

According to the ISP implementation as in 40-1, the multichanneltransceiver 44-1 provides functions analogous to the multichanneltransceiver 26 of the subscriber unit, but in an inverse fashion. Thesame is true of the protocol converter 46-1, that is, it providesinverse functionality to the protocol converter 25 in the subscriberunit 120. The ISP 40-1 accepts data from the protocol converter 46-1 inthe TCP/IP frame format and then communicates such data to the Internet49-1. It should be understood that the configuration of the remainingISP equipment 48-1 may take any number of forms such as a local areanetworks, multiple dial up connections, T1 carrier connection equipment,or other high speed communication links to the Internet 49-1.

The service provider 40 optionally includes a radio base station in acellular telephone system or wireless local loop (WLL), permitting adial-up connection between the remote transceivers 160 and server 49-2.In this instance, the base station 40-2 includes an antenna 42-2,multichannel transceiver 44-2, and protocol converter 46-2 providing oneor more connections to a public switched telephone network (PSTN) 48-2,and ultimately to the server 49-2.

In addition to the illustrated implementations 40-1 and 40-2, there maybe various other ways of implementing the provider 40 in order toprovide a connection to data processing equipment from the terminalequipment coupled to remote transceivers 160.

Turning attention now to the functions of the protocol converters 25 and46, they can be thought of as intermediate layer within the context ofthe Open System Interconnect (OSI) model for communication. Inparticular, the protocol converter provides a bandwidth managementfunctionality 29 implemented between a physical layer such as providedby the CDMA protocol in use with the multichannel transceivers 26 and anetwork layer protocol such as TCP/IP providing connections between theterminal equipment 22 and the Internet 49-1 or server 49-2.

The bandwidth management functionality 29 preferably provides a numberof functions in order to keep both the physical layer and network layerconnections properly maintained over multiple communication links 30.For example, certain physical layer connections may expect to receive acontinuous stream of synchronous data bits regardless of whetherterminal equipment at either end actually has data to transmit. Suchfunctions may also include rate adaption, bonding of multiple channelson the links, spoofing, radio channel setup and takedown.

The present invention is more particularly concerned with the techniqueused by the protocol converters 25 and 46 for adjusting the frame sizeof individual channels used over each of the multiple links 30 in orderto improve the effective throughput rate between a sender and a receiverin a bit error rate prone environment. It should be understood in thefollowing discussion that the connections discussed herein arebidirectional, and that a sender may either be the subscriber or accessunit 120 or the provider unit 40.

More specifically, the problem addressed by the present invention isshown in FIG. 3. A frame 60 as received at the receiver end must beidentical to the frame 50 originating at the sender. This is despite thefact that multiple channels are used with much higher bit error rateswith the received frame 60 being transmitted reliably with a bit errorrate of 10.sup.-6 or better as is typically required in TCP/IP or othernetwork layer protocols. The present invention optimizes the effectivedata throughput such that the received frames 60 are not affected by theexperienced bit error rate performance of network layer connections.

It should be understood that another assumption is that the individualchannels 30-1, 30-2 . . . 30-N may experience different bit error ratelevels both over time and in an average sense. Although each of thechannels 30 may operate quite similarly, given the statistical nature oferrors, identical behavior of all of the channels 30 is not assumed. Forexample, a specific channel 30-3 may receive severe interference fromanother connection in a neighboring cell, and be capable of providingonly a 10.sup.-3 whereby other channels 30 may experience very littleinterference.

In order to optimize the throughput for the system 10 on a global basis,the invention also preferably optimizes the parameters of each channel30 separately. Otherwise, a relatively good channel 30-1 might sufferdown speed procedures required to accommodate a weaker channel 30-3.

It should also be understood that the number of channels 30 necessary tocarry a single data stream such as a rate of 128 kbps at a given pointin time can be relatively large. For example, up to 20 channels 30 areassigned at a particular time in order to accommodate a desired datatransfer rate. Therefore, the probability of different characteristicsin any given one of the channels 30 is significantly different.

Turning attention now more particularly to FIG. 4, the operations of theprotocol converter 25 or 46 at the sender will be more particularlydescribed. As shown, the input frame 50 as received from the networklayer is relatively large, such as for example 1480 bits long, in thecase of a TCP/IP frame.

The input frame 50 is first divided into a set of smaller pieces 54-1,54-2. The size of the individual pieces 54 are chosen based upon theoptimum subframe size for each of the channels 30 available. For examplea bandwidth management function may make only a certain number ofchannels 30 available at any time. A subset of the available channels 30is selected, and then the optimum number of bits for each subframeintended to be transmitted over respective one of the channels is thenchosen. Thus as illustrated in the FIG. 4, a given frame 54-1 can bedivided into pieces associated with four channels. At a later time,there may be nine channels 30 available for a frame, with differentoptimum subframe sizes for the piece 54-2.

Each of the subframes 56 consists of a position identifier 58 a, a dataportion 58 b, and a trailer typically in the form of an integritychecksum such as a cyclic redundancy check (CRC) 58 c. The positionidentifier 58 a for each subframe indicates the position within theassociated larger frame 50.

The subframes 56 are then further prepared for transmission on eachchannel 30. This may be done by adding a sequence number related to eachchannel at the beginning of each subframe 56. The subframe 56 is thentransmitted over the associated channel 30.

FIG. 5 illustrates the operations performed at the receive side. Thesubframes 56 are first received on the individual channels 30. Asubframe 56 is discarded as received if the CRC portion 58 c is notcorrect.

The sequence numbers 58 d of the remaining frames 56 are then strippedoff and used to determine whether any subframes 56 are missing. Missingsubframes 56 can be detected by comparing the received sequence numbers58 d. If a sequence number is missing, it is assumed that the associatedsubframe 56 was not received properly. It should be understood thatappropriate buffering of data and subframes 56 is typically required inorder to properly receive the subframes 56 and determine if there areany missing sequence numbers depending upon the transmission rates,number of channels 30 and propagation delays in effect.

Upon the detection of a missing subframe 56, retransmission of themissed subframe is requested by the receiving end. At this point, thetransmitting end reperforms transmission of the missing subframe.

Once all of the subframes 56 are received, the position number 58 a isthen used to arrange the data from the subframes 56 in the proper orderto construct the output received frame 60.

At this point, also, if any piece of the large output frame 60 is stillmissing, such as when an end of frame command is encountered,retransmission of the corresponding subframe can also be requested atthe indicated position, specifying a length for the missing piece.

Because of the use of both the position and sequence numbers, the senderand receiver know the ratio of the number of subframes received witherrors to the number of frames received without errors. Also, thereceiver and sender know the average subframe length for each channel.The optimum subframe size can thus be determined for each channel fromthese parameters as will be described more fully below.

One example of where the principles of the present invention as shown inFIG. 1 are particularly useful is a remote site such as a trade show. Ithas been increasingly prevalent that sales people at trade shows relyheavily on computers to convey information to customers throughtutorials and demonstrations. In many cases, information must beaccessed from a remote location and retrieved on demand at a trade showsite. Hence, there is an immediate need for each salesperson to haveaccess to a hi-speed network connection.

One method to provide network access for salespeople is to supply themwith a direct hardwired network link. The use of such a link has severaldrawbacks. Renting the use of a hardwired link from trade showfacilities is often very expensive due to monopolistic tendencies of thefacility owners. Admittedly however, such links can be tedious andtherefore costly to maintain in this ever-changing environment.Typically, there are no viable alternatives for allowing patrons toestablish high speed communication links with remote networks, otherthan through these hardwired links supplied by the trade show facility.

Even if a hardwired link is available at a reasonable rate, thehard-wired links are usually restrictive because computers connected tosuch links are tethered to a cable, preventing mobility of the operator.Needless to say, it is sometimes important that a salesperson approachthe customer to make a sale.

For example, a potential customer may quickly lose interest in a boothand related products if they have to stand in line to speak with asalesperson, perhaps to the point that they also do not leave a businesscard. If properly noted, salespeople can be dispatched on down times toultimately track down potential customers who showed an interest intheir booth but were too busy to provide adequate attention at the time.Accordingly, a salesperson could optionally “hunt” the entire trade showfloor with a computer at his side and, if needed, retrieve volumes ofdata available on demand over a hi speed network interface such ascommunication system 190. Hence, for these and other reasons, there isstrong desire to operate communicate with a network on a wireless basisbecause of the mobile flexibility that it affords. Alternative methodsof establishing a link, such as individual connections via a modem andcellular telephone link, provide only low speed data transfers such as14.4 KBPS.

In addition to increased mobility, combined hub 100 and access unit 120makes it possible for a trade show participant to provide their ownlower cost wireless 5 connection to a base station 130 in furthercommunication with a network 140. Additionally, the low reliability ofhaphazardly laid network cables no longer negatively impacts sales atthe show due to cable failures.

The principles of the present invention are also advantageously deployedat large multi-corporate meetings, where participants using laptopcomputers require access to either the Internet or their own network anddata bases. A group of corporate representatives attending an off-sitemeeting from a single corporation can advantageously supply their owncomputer network connections by locating combined hub 100 and accessunit 130 in an immediate off-site corporate location to be supported.For example, business executives can access limitless information at theremote location. A computer in wireless range of the hub is free toaccess almost limitless information over the communication system in alocation such as a boardroom or, alternatively, other locations in abuilding because the first wireless communication link 150 is operablethrough walls and the like. This topology also provides security becauseit is essentially private. Communications directed over ones ownnetwork, such as E-mail or the like, are therefore secure fromintrusion.

It should be noted that there are many other possible applications ofthe present invention and that the use of the previously describedapplications are merely exemplary for pointing out some of itsadvantageous features.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

1. A method for use in a mobile communication device, the methodcomprising: receiving, at the mobile communication device, a firstwireless communication signal according to a cellular communicationprotocol; recovering a first data packet from the first wirelesscommunication signal; and transmitting the first data packet accordingto an IEEE 802.11 wireless communication protocol.
 2. The method ofclaim 1, further comprising: receiving, at the mobile communicationdevice, a second wireless communication signal according to the IEEE802.11 wireless communication protocol; recovering a second data packetfrom the second wireless communication signal; and transmitting thesecond data packet according to the cellular communication protocol. 3.The method of claim 1, wherein the receiving the first wirelesscommunication signal includes receiving the first wireless communicationsignal from a cellular base station.
 4. The method of claim 1, whereinthe transmitting the first data packet includes transmitting the firstdata packet to an IEEE 802.11 user device.
 5. The method of claim 1,wherein the cellular communication protocol is a code division multipleaccess (CDMA) protocol.
 6. The method of claim 5, wherein the receivingthe first wireless communication signal includes receiving the firstwireless communication signal via a plurality of CDMA channels.
 7. Themethod of claim 1, wherein the first data packet includes a TransmissionControl Protocol/Internet Protocol (TCP/IP) packet.
 8. The method ofclaim 7, wherein the receiving the first wireless communication signalincludes: receiving a plurality of TCP/IP packet portions associatedwith the TCP/IP packet; and combining the plurality of TCP/IP packetportions to recover the TCP/IP packet.
 9. The method of claim 8, whereineach of the plurality of TCP/IP packet portions includes a positionidentifier indicating a position of the respective TCP/IP packet portionwithin the TCP/IP packet.
 10. The method of claim 8, wherein thereceiving the first wireless communication signal includes transmittinga retransmission request indicating a TCP/IP packet portion, on acondition that the TCP/IP packet portion is associated with a receptionerror.
 11. A mobile communication device comprising: circuitryconfigured to: receive a first wireless communication signal accordingto a cellular communication protocol; recover a first data packet fromthe first wireless communication signal; and transmit the first datapacket according to an IEEE 802.11 wireless communication protocol. 12.The mobile communication device of claim 11, wherein the circuitry isconfigured to: receive a second wireless communication signal accordingto the IEEE 802.11 wireless communication protocol; recover a seconddata packet from the second wireless communication signal; and transmitthe second data packet according to the cellular communication protocol.13. The mobile communication device of claim 12, wherein the circuitryis configured to receive the first wireless communication signal from acellular base station.
 14. The mobile communication device of claim 12,wherein the circuitry is configured to transmit the first data packet toan IEEE 802.11 user device.
 15. The mobile communication device of claim12, wherein the cellular communication protocol is a code divisionmultiple access (CDMA) protocol.
 16. The mobile communication device ofclaim 11, wherein the circuitry is configured to receive the firstwireless communication signal via a plurality of CDMA channels.
 17. Themobile communication device of claim 12, wherein the first data packetincludes a Transmission Control Protocol/Internet Protocol (TCP/IP)packet.
 18. The mobile communication device of claim 11, wherein thecircuitry is configured to receive the first wireless communicationsignal by: receiving a plurality of TCP/IP packet portions associatedwith the TCP/IP packet; and combining the plurality of TCP/IP packetportions to recover the TCP/IP packet.
 19. The mobile communicationdevice of claim 18, wherein each of the TCP/IP packet portions includesa position identifier indicating a position of the respective TCP/IPpacket portion within the TCP/IP packet.
 20. The mobile communicationdevice of claim 19, wherein the circuitry is configured to receive thefirst wireless communication signal by transmitting a retransmissionrequest indicating a TCP/IP packet portion, on a condition that theTCP/IP packet portion is associated with a reception error.